This invention relates to seals for bearings, especially for universal joints. Such bearings are comprised of a bearing element, such as a shell, with a sealing ring arranged in the bore of the shell. The sealing ring extends to engage, with its sealing surface, the cylindrical surface of a machine element positioned within the bearing element. The machine element may be the pin of the universal joint. Arrangements of this type further comprise an additional elastic sealing ring positioned between the open end of the bearing element and a shoulder on the machine element, the sealing rings and bearing elements constituting a prefabricated element.
A sealing ring of this type, for bearings for universal joints, is disclosed in DE-OS No. 2,144,172. Therein is described a seal consisting of two sealing rings, of which one is arranged in the cylindrical bore of the bearing element, the bore also serving as the race for the rolling bodies. The sealing ring extends between the face sides of the rolling bodies and a restraining flange in the bore of the bearing element. The other sealing ring is arranged between the open end of the bearing element and a shoulder on the universal joint pin which extends into the bearing. This other sealing ring is provided with projections or a circular collar which grip under the restraining flange of the bearing element. The sealing rings are thus combined with the bearing element to form a prefabricated unit.
This known arrangement has the disadvantage that the edge between the end of the bearing element and the rolling bodies can be flanged only after the fabrication of the bearing. For this purpose, the region of the edge of the bearing element is not hardened. This requires that either this zone is masked in the hardening of the bearing, or that a supplementary annealing process be employed. In addition to the increased expense of this additional process step, there is the danger that the hardness of the race for the rolling bodies will be adversely affected. Further, this known arrangement has the disadvantage that the length of the bearing element is relatively large in view of the necessity for providing the restraining flange, and the production of the bearing is thereby rendered more difficult. Finally, the known arrangement has the disadvantage that the escape of air in the bearing, and of excess lubricating material is hindered during the pressing of the bearing element and the seals thereon onto the universal joint. Consequently, there is the danger that during the pressing of the bearing element on the universal joint pin, or in the prefabricated condition following lubrication of the rolling element through the high pressure of the part or seal, damage or destruction of the element can result. On the other hand, in spite of the use of high pressure for the forcing of lubricating material into the bearing, it is not assured that all hollow spaces of the bearing will be filled with the lubricating material.
In order to avoid these disadvantages, DE-OS No. 2,718,503 describes a sealed universal joint in which an elastic sealing ring is provided between the open end of the bearing and a shoulder of the universal joint pin. The elastic sealing ring forms a part of the assembly of the bearing, and is provided with an axially extending air escape groove. The groove is sealed to the modified end of the bearing element preferably by means of an elastic sealing lip cooperating with the shoulder of the universal joint, against outside influence. In this arrangement, the space in the presealing lip is not filled with grease. Further, this known arrangement has a complicated shape, which therefore requires the relatively complicated and consequently expensive tools for its production.
It is therefore the object of this invention to provide a sealing arrangement for a bearing, which employs a simple construction for the individual sealing element as well as simple technique for affixing them to the bearing element, to form a prefabricated unit. It is further the object of this invention to provide a sealing arrangement wherein lubrication under high pressure is permissible, and the lubricant flows into the bearing with a higher speed, without resulting damage or destruction of the part, and also wherein lubrication of all of the hollow spaces of the bearing is provided even with the use of a small pressure.